Rigid Packages Having Peelable Hermetic Seals

ABSTRACT

The disclosed principles provide for a welding technique welding the flanges of a rigid lid sealed onto a rigid tray, such that the two may be easily separated but still repeatedly reclosable such that the rigid package may be reused. For this unique and advantageous ultrasonic welding technique, the disclosed principles provide for the inclusion of a unique delamination layer between the similar rigid materials used for forming the flanges of both the lid and the tray. The disclosed principles provide for the delamination layer to be provide on one or both of the two rigid materials, but behind the seal interphase area so that the hermitic seal may still be created. This delamination layer operates such that it peels apart (i.e., delaminates) as the ultrasonically sealed rigid material of the lid flange and rigid material of the tray flange are pulled apart while opening the package initially.

TECHNICAL FIELD

The present disclosure relates to snack packages, and in particular to a technique for sealing rigid packages, for example those used for food products.

BACKGROUND

Various container and package designs have been used in the past to contain and display snack food products. Among the many existing snack containers and packages, some have contained multiple compartments for separately holding different types of snack products in a single package. For example, U.S. Pat. No. 5,657,874, Hustad et al., describes a rigid plastic base tray having at least three compartments covered with a flexible film that hermetically seals each of the compartments. U.S. Pat. No. 5,853,105, Roman et al., discloses a circular container comprised of two compartments hermetically sealed by a film placed over the top of the two compartments. U.S. Pat. No. 5,277,920, Weaver, Jr., discloses a food package consistent of two separate compartments covered by sealing means. However, each of these conventional snack packages provide multiple compartments for holding various snack products that are downwardly formed from an upper flat surface of the rigid container. Flexible film is used them laid across this upper flat surface to provide a seal for the snacks held in the downwardly formed compartments.

Unfortunately, this conventional design of multi-compartment snack packages suffers from several disadvantages. For example, the downwardly formed compartments only permit access to the various snack products held therein from the top of each compartment. This can often make it difficult for a consumer to reach down into a compartment to grasp the product, especially if the compartment(s) are relatively deep and the quantity of remaining snack product in such compartment(s) is low. Additionally, the products held in the various downwardly formed compartments are not readily visible to consumers. Thus, if such conventional multi-compartment packages are stacked on a display shelf, consumer may have to pick up a package and turn it in various directions to ascertain exactly what is held in each downwardly formed compartment. Furthermore, such conventional packages with downwardly formed compartments typically form the compartments of flexible or semi-flexible material, which permits easier crushing of the products within the compartments should external forces, including the mere grasping of the container by a consumer, be applied to the sides of one or more of the compartments.

Still further, the peelable films laid over the top surfaces of such conventional multi-compartment packages is not typically resealable over the package once it is open. Even in packages where the film can be laid back over the top surface of the package, the consumer's view of what product(s) remain in the various downwardly formed compartments is again obscured. Moreover, the mere use of flexible films over the top surfaces of such conventional multi-compartment snack packages is a weak material, which can be easily punctured during shipping of such packages or even the stacking of multiple similar packages on a display shelf.

Even in conventional packages having both rigid trays and rigid lids, when such rigid packages are configured to be reclosable for later and repeated use, such packages do not lend themselves for use with food products. More specifically, most packages for use with food products must be closed by the packager so that the food product is not exposed to external contaminants, such as dirt or even insects. As a result, food product packages are typically hermetically sealed. One conventional approach to seal such rigid, reclosable packages is to use an adhesive between to the rigid lid and rigid tray to provide the hermetic seal. However, the use of adhesives with food products is typically undesirable since higher temperatures can potentially cause flowing of the adhesive, which could contaminate the food product within or simply lose the integrity of the hermetic seal. Even excessive age can also reduce the effectiveness of such adhesives, again leading to potential loss in seal integrity. Moreover, adhesive residue tends to remain on the sealing surfaces of either or both the rigid lid or rigid tray, which leads to sticky mating surfaces between the two. Such remaining residue can also be a magnet for unwanted dust or other debris to collect on the mating surfaces.

Another conventional approach to creating a hermetic seal between the mating surfaces of a rigid lid and tray is to weld the mating surfaces. Such welding techniques may include both heat welding or ultrasonic welding techniques. However, while such welding of the rigid lid to a rigid tray can be effective in creating a hermetic seal for the package, welding the mating surfaces of the lid and tray does not result in a peelable seal that permits the repeated reclosing of the rigid lid over the rigid package. Specifically, such welding of the mating surfaces typically results in a permanent joining of the two surfaces, creating a destructive seal between the two. This is especially the case for ultrasonic welding where the mating pieces need to be made from the same or very similar material. Ultrasonically welding like materials essentially creates a single layer of that material, which is again a destructive seal between the two pieces. Consequently, attempting to peel apart these ultrasonically welded materials destroys the welded mating surfaces. For example, of one mating surface may remain on the other and vice versa, or tearing of the package may occur in other areas around the original mating surfaces. In either situation, the connecting portions of the rigid lid and rigid tray do not maintain a smooth, uniform surface that lends itself to reclosing of the lid onto the tray.

Therefore, there is a need for an improved rigid package for holding food products, and related technique for sealing such rigid food packages, that does not suffer from these and other deficiencies found in conventional packages. The disclosed principles provide such improved package and sealing technique.

SUMMARY

To overcome the deficiencies of the prior art, the disclosed principles provide packages having a rigid lid, which thus offers far better protection for the enclosed products. Moreover, the rigid lid in the disclosed packages is reclosable on to the rigid tray, which allows the unique disclosed packages to be reusable if desired. Also, the rigid material comprising the disclosed trays prevents crushing of food products as often occurs in downwardly formed compartments found in conventional packages, which are formed of thinner, less rigid materials. For providing the hermitic sealing of a disclosed exemplary rigid package, the disclosed principles for a unique manner for sealing the rigid lid onto the rigid tray of such packages. This sealing technique allows the packaged to be hermetically sealed when provided by the original manufacturer/packager, but where the seal is breakable so as to remove the rigid lid from the rigid tray. More specifically, in order to provide hermitic sealing of the entire package, the seal is formed entirely around the perimeter of the package, and specifically may be provided where the flange of the lid's skirt meets the flange of the tray's skirt. While providing a seal between the meeting flanges of a lid and a tray is not on its own unique, it is how that seal is provided by the disclosed principles that is.

Accordingly, the disclosed principles provide for a welding technique for use in welding the flanges of a rigid lid sealed onto a rigid tray, such that the two may be easily separated but still repeatedly reclosable such that the rigid package may be reused. For this unique and advantageous ultrasonic welding technique, the disclosed principles provide for the inclusion of a unique delamination layer between the similar rigid materials used for forming the flanges of both the lid and the tray. To ultrasonically weld two rigid plastics sufficiently to provide a hermetic seal, both rigid materials should have the same or very similar material composition or chemistry in the welding interphase area in order for a satisfactory seal to be provided between the two. The disclosed principles provide for the delamination layer to be provide on one or both of the two rigid materials, but behind the seal interphase area so that the hermitic seal may still be created. This delamination layer operates such that it peels apart (i.e., delaminates) as the ultrasonically sealed rigid material of the lid flange and rigid material of the tray flange are pulled apart while opening the package initially. Moreover, this delamination layer may be coextruded with the sealant layer on one or both of the rigid materials.

In one aspect, hermetically sealed reclosable packages having rigid lids and rigid trays are provided. In one exemplary embodiment of such a hermetically sealed package, the disclosed package comprises a first flange comprised of a rigid plastic and having a first mating surface, and a first laminated layer disposed on the first mating surface of the first flange, wherein the first laminated layer comprises a delamination layer and a sealant layer positioned as the outermost layer of the first laminated layer. In addition, such an exemplary reclosable package comprises a second flange comprised of a rigid plastic and having a second mating surface configured to be ultrasonically welded to the first mating surface, and a second laminated layer disposed on the second mating surface of the second flange, wherein the second laminated layer comprises a sealant layer positioned as the outermost layer of the second laminated layer. In such embodiments, the first and second mating surfaces with the first and second laminated stacks interposed are ultrasonically welded to one another such that the first and second sealant layers are hermetically sealed. The hermetically sealed rigid package may then be opened by peeling the lid flange from the tray flange, which delaminates the delamination layer leaving substantially smooth surfaces between remaining lid and tray flanges, which in turn allow the rigid package to be easily reclosed repeatedly without interference from a destroyed interface between the original rigid flanges.

In other aspects, methods for providing a peelable hermetic seal on a rigid package are disclosed. In one embodiment, such an exemplary method may comprise providing a first flange comprised of a rigid plastic and having a first mating surface, and forming a first laminated layer on the first mating surface of the first flange, wherein the first laminated layer comprises a delamination layer and a sealant layer positioned as the outermost layer of the first laminated layer. Such an exemplary method may further comprise providing a second flange comprised of a rigid plastic and having a second mating surface configured to be ultrasonically welded to the first mating surface, and forming a second laminated layer on the second mating surface of the second flange, wherein the second laminated layer comprises a sealant layer positioned as the outermost layer of the second laminated layer. Also, such an method includes ultrasonically welding the first and second mating surfaces with the first and second laminated stacks interposed therebetween such that the first and second sealant layers are hermetically sealed to one another.

Numerous embodiments and advantages associated with each such embodiment are discussed in further detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description that follows, by way of non-limiting examples of embodiments, makes reference to the noted drawings in which reference numerals represent the same parts throughout the several views of the drawings, and in which:

FIG. 1 illustrates a top view of one embodiment of a rigid multi-compartment reclosable package designed and constructed in accordance with the disclosed principles;

FIG. 2 illustrates a side cross-sectional view of a rigid package taken along line 2-2 of the rigid package illustrated in FIG. 1;

FIG. 3 illustrates a close up cross-sectional detail view of a portion of the rigid package illustrated in FIG. 2.

FIG. 4 illustrates a block diagram presenting a cross-sectional view of a portion of one of the rigid lid flange or rigid tray flange of a package constructed in accordance with the disclosed principles;

FIG. 5 illustrates a block diagram presenting a cross-sectional close-up view of a portion of an exemplary composition of the extruded sealant layer shown in FIG. 4 in accordance with the disclosed principles;

FIG. 6 illustrates a block diagram presenting a cross-sectional view of a portion of both the rigid lid flange and the rigid tray flange of a reclosable package constructed in accordance with the disclosed principles;

FIG. 7 illustrates a block diagram presenting a cross-sectional view of the portion of both the rigid lid flange and the rigid tray flange shown in FIG. 6 joined together;

FIG. 8 illustrates a block diagram presenting a cross-sectional view of the portion of lid flange and the tray flange shown in FIGS. 6 and 7 with a part of the lid flange separated along the delamination layer in accordance with the disclosed principles;

FIG. 8A illustrates a first plot of peel force of two rigid plastics ultrasonically welded in accordance with certain welding parameters in accordance with the disclosed principles;

FIG. 8B illustrates a second plot of peel force of two rigid plastics ultrasonically welded in accordance with certain welding parameters in accordance with the disclosed principles;

FIG. 9 illustrates a top view of a second embodiment of a rigid multi-compartment reclosable package constructed in accordance with the disclosed principles;

FIG. 10 illustrates a side cross-sectional view of the package of FIG. 9 taken along line 10-10; and

FIG. 11 illustrates a close up cross-sectional detail view of a portion of the rigid package illustrated in FIG. 10.

DETAILED DESCRIPTION

In view of the foregoing, through one or more various aspects, embodiments and/or specific features, the present disclosure is intended to bring out one or more of the advantages that will be evident from the description. The present disclosure makes reference to one or more specific embodiments by way of illustration and example. It is understood, therefore, that the terminology, examples, drawings and embodiments are illustrative and are not intended to limit the scope of the disclosure.

FIG. 1 illustrates a top view of one embodiment of a rigid multi-compartment reclosable package 100 designed and constructed in accordance with the disclosed principles. From this top view, this embodiment of the package 100 is formed having four sides, and in the shape of a square, although any other shapes may also be formed. Also, the four corners of the package 100 are rounded off. The package 100 is comprised of a rigid lid 105 fitted over and onto a rigid tray 110. The rigid lid 105 of the package 100 is semi-transparent in this embodiment, which allows visibility of a piece of product 115 being held within the package 100. As used herein, the terms “rigid” and “rigid material” are used to mean a material having sufficient resiliency to maintain its form or shape even though the material has some amount of flexibility to be temporarily distorted.

Also visible from this top view are a lid tab 105 a and tray tab 110 a, which in this embodiment may be grasped by a consumer and pulled in opposite directions, with the lid tab 105 a being pulled upwardly and the tray tab 110 a being pulled downwardly and away from the lid tab 105 a, to separate the lid 105 from the tray 110. Texture features 105 b and 110 b may also be provided on the respective tabs 105 a, 110 a, to assist the consumer in maintaining their grasp of the tabs 105 a, 110 a when used to open the package 100 in this manner.

FIG. 2 illustrates a side cross-sectional view of a rigid package 100 taken along line 2-2 of the rigid package 100 illustrated in FIG. 1. From this cross-sectional view, both a rigid lid 105 and a rigid tray 110 of this embodiment of the package 100 can be seen, where the lid 105 is removably fastened onto the tray 110. This cross-sectional view also shows the uniquely shaped raised walls 120 that extend from the bottom surface of the rigid tray 110 to the underside of the lid 105 to create multiple compartments on the tray 110 for holding products, such as snack foods.

In this embodiment, the dividing walls 120 are shown as tapered or sloped from the center of the tray 110 towards the outer periphery of the tray 110. The slope of the walls 120 are such that the bottom periphery of the tray 110 includes a raised lip 110 c that helps secure the product 115 held on the tray 110 from sliding off of the tray 110 when the lid 105 is removed. This tapered structure for the walls 120 permits partial viewing of the product 115 within the package 100 from the side by a consumer in those embodiments having a transparent or semi-transparent lid 105. Also, the sloped walls 120 allow easier grasping of the product 115 on the tray 110 by a consumer's fingertips once the lid 105 is removed from the tray 110.

Formation of the walls 120 and the tray 110 may be done in a single, unitary piece of rigid material by any viable plastic formation technology, or the walls 120 may simply be attached to the interior, bottom surface of the tray 110. In such latter embodiments, the walls 120 may all be formed in a single piece, and then that piece attached or otherwise affixed to the interior, bottom surface of the tray 110, or one or more of the walls 120 may be formed separately, and then the two or more pieces comprising the walls 120 attached or otherwise affixed to the interior, bottom surface of the tray 110. This embodiment of the package 100 may also include walls 120 that form any number of compartments on the tray 110 for holding product(s) 115. And it should be noted that while the four compartments created on the tray 110 of FIGS. 1 and 2 are of substantially equal dimensions and sizes, compartments formed on the tray of a package in accordance with the disclosed principles may of any size and shape with respect to one another, and no limitation to any particular size or shape or even the number of compartments is implied or should be inferred.

Still further, the dimensions and slope of the walls 120 can be different from those in this illustrated embodiment. For example, in this embodiment of the package 100, the walls 120 not only have a thickness that tapers upwardly, where the base of each wall 120 is thicker than the top of each wall 120, but the walls 120 also have a taper as you move from the center of the tray 110 to the periphery of the tray 110. The upward tapering of the shape of the walls 120 is typical for those trays and walls manufactured using vacuum forming or injection molding, but may also be so tapered as an ornamental feature. Also, the overall thicknesses of the walls 120, whether at the top or bottom of a wall 120, or at the center-most or outer-most portion of a wall 120, can be selected as desired for each application. And similarly, the angle of the slope of each wall 120, when moving from the center of the tray 110 to the periphery of the tray 110 may also be different from the illustrated embodiment. Such sloping may also be included on less than all of the walls 120, if desired, and the slope on one or more of the walls 120 may be formed as a straight line, a curved line, or as in this illustrated embodiment, as a combination of partially curved and partially straight when moving from the center to the periphery of the tray 110. Still further, the slope of the tops of the wall(s) 120 may be reversed so that they slope from the periphery of the tray 110 downward to the center of the tray 110. Of course, a combination of upwardly and downwardly sloping walls may also be employed in a package constructed in accordance with the disclosed principles.

Also visible from the cross-sectional view of FIG. 2 are a lid skirt 125 and a tray skirt 130. Each skirt 125, 130 in this embodiment of a package 100 in accordance with the disclosed principles is formed in an outward and downward configuration. Additionally, the skirts 125, 130 are preferably formed coextensive with one another, and in corresponding complimentary shapes. Such complimentary formation of the lid skirt 125 and the tray skirt 130 allows the skirts 125, 130 to be used as a closing fastening feature for the package 100. Specifically, the lid skirt 125 may be secured over the tray skirt 130 when fitting the lid 105 onto the tray 110. The rigid materials used to form the lid 105 and the tray 110 provide a minimum amount of resiliency along with flexibility to the corresponding skirts 125, 130. This results in the skirts 125, 130 maintaining their overlapping positioning so as to keep the lid 105 snapped onto the tray 110. However, this also allows the lid skirt 125 to be flexed outwardly, away from the tray skirt 130 temporarily so that the lid 105 may be lifted off of the tray 110. The outer walls of the skirts 125, 130 may also be formed with a securing feature 135 to assist with maintaining the joining of the lid skirt 125 with the tray skirt 130.

Additionally, for this embodiment of the package 100, the ends of the skirts 125, 130 each further include a flange 125 a, 130 a laterally extending outward from the bottom ends of each skirt 125,130. The flanges 125 a, 130 a, in this embodiment, are formed coextensive with one another, and may be used create a seal for the package 100 that may be pealed apart by the consumer. The formation of such a seal using the flanges 125 a, 130 a is discussed in detail below, and such a seal can be provided at the factory packaging the products 115 for sale in the package 100, and thus permits the package 100 to hold any of the types of food products requiring hermetic sealing. Also, in this embodiment, the flanges 125 a, 130 a extend horizontally from their corresponding skirts 125, 130; however, the disclosed principles are not so limited. Thus, similar flanges 125 a, 130 a may be formed to extend in other directions as well. Moreover, although the flanges 125 a, 130 a are flat in this embodiment, a package in accordance with the disclosed principles may also include flanges 125 a, 130 a having a different shape, such as curved in either an upward or downward direction.

FIG. 3 illustrates a close up cross-sectional detail view of a portion of FIG. 2. This close up view illustrates the joined lid and tray skirts 125, 130 joined together when the lid 105 is closed onto the tray 110. From this close up view, the complimentary, outward and downward shapes of the lid skirt 125 and the tray skirt 130 can be seen. Thus, the rigid materials used to form the lid 105 and the tray 110 provide a minimum amount of resiliency along with flexibility to the corresponding skirts 125, 130. This results in the skirts 125, 130 maintaining their overlapping positioning so as to keep the lid 205 snapped onto the tray 110. However, this also allows the lid skirt 125 to be flexed outwardly, away from the tray skirt 130 temporarily so that the lid 105 may be lifted off of the tray 110. Also, securing features 235, which in this embodiment are formed as corresponding concave (inward) curvatures on the downward portions of the skirts 125, 130, can also be seen. These securing features 135, of which any number may be included at various locations around the package 100, assist in securing the lid 105 onto the tray 110 because its curvature is inward (i.e., concave) while the upper curvature of the skirts 125, 130 is in the opposite outward direction (i.e., convex). These opposing curvatures work in concert to keep the lid skirt 125 from slipping off of the tray skirt 130, thereby allowing opening and reclosing of the lid 105 and the tray 110. The lid tab 105 a and the tray tab 110 a may be used by the consumer to pull apart and thereby overcome the securing feature, and thus separate the lid skirt 125 from the tray skirt 130 to open the package 100. Of course, other shapes for securing features on the package 200 may also be employed. Also, additional structures and features may also be provided for a rigid package designed and constructed in accordance with the disclosed principles, such as those disclosed in co-owned U.S. patent application Ser. No. ______, (Attorney Docket No. CQKER.4041), the disclosure of which is hereby incorporated by reference.

The unique structure and features of the package 100 illustrated in FIGS. 1-3, as well as the embodiments discussed in detail below in the co-pending application mentioned above and incorporated by reference herein, offer significant advantages over conventional food product packages. For example, conventional packages typically include downwardly formed compartments in a rigid or semi-rigid tray, where the food product is placed down in the compartments. A thin, flexible film is then laid over the top surface of the conventional tray to cover the top openings of the downwardly formed compartments, and thus cover the product held within those compartments. However, the rigid tray 110 having sloping walls 120 extending upwardly, rather than the downwardly formed compartments typically found in conventional packages, permits easier visibility of the food products 115. Moreover, by employed sloping walls 120 when moving from the center of the tray 110 towards its perimeter, the product 115 held on the rigid tray 110 is easily graspable by a consumer.

Additionally, instead of the thin flexible film used in conventional packages, the disclosed principles provide packages having a rigid lid, which thus offers far better protection for the enclosed products. Moreover, the rigid lid in the disclosed packages is reclosable on to the rigid tray, which allows the unique disclosed packages to be reusable if desired. Also, the rigid material comprising the disclosed trays prevents crushing of food products as often occurs in downwardly formed compartments found in conventional packages, which are formed of thinner, less rigid materials. Still further, the upwardly formed walls of the disclosed packages may be formed as hollow walls, as shown in FIG. 2. Such hollow formed walls, combined with the raised lip 110 c of the tray 110 having a slight taper, also as seen in FIG. 2, which allows multiple trays 110 of the same embodiment of the package 100 to be stackable/nestable. Likewise, the slight taper to the rigid lid 105, again shown in FIG. 2, allows multiple lids 105 of the same embodiment to also be stackable. Such ability to stack multiple lids and trays of a disclosed package is particularly useful if the rigid material used to construct the lids 105 and trays 110 is washable and reusable, since many packages 100 can thus be cleaned and saved for repeated use by a consumer. Furthermore, as mentioned above, the rigid tray 110 having the sloped upwardly extending walls 120 creates a unique package where the product(s) held in the tray compartments is more readily visible from the side of the package 100. The rigid lids 105 may also be formed of transparent or semi-transparent material, which also viewing of the product(s) 115 therein by consumers without having to open or even pick up the package 100. As such, packages in accordance with the disclosed principles provide for unique product displaying to the surrounding environment versus conventional snack packages, such as the conventional downwardly formed trays mentioned above, or even stand up snack bags, because the product(s) is more readily visible from the package's surroundings and because of the unique shapes of the rigid lids 105 and trays 110. All of these advantages, and even further advantages discussed below, may be achieved with all of the various embodiments of the rigid packages in accordance with the disclosed principles.

For providing the hermetic sealing of a disclosed exemplary rigid package, the disclosed principles for a unique manner for sealing the rigid lid onto the rigid tray of such packages. This sealing technique allows the packaged to be hermetically sealed when provided by the original manufacturer/packager, but where the seal is breakable so as to remove the rigid lid from the rigid tray. More specifically, in order to provide hermitic sealing of the entire package, the seal is formed entirely around the perimeter of the package, and specifically may be provided where the flange of the lid's skirt meets the flange of the tray's skirt. While providing a seal between the meeting flanges of a lid and a tray is not on its own unique, it is how that seal is provided by the disclosed principles that is. As discussed above, conventional techniques for sealing the rigid lid and rigid tray of a package comprised of plastic is to either use an adhesive of some sort or to use a welding technique to join the two together.

In those cases where adhesive are not desirable for use on reclosable packages, as discussed above, ultrasonic welding techniques may be used. But as mentioned above, welding the flanges of the two components together is also not conducive for rigid packages that are intended to be reclosable in those cases when not all of the product within has been finished, or intended to be reusable such as when the package is desirable for reuse by consumers. Specifically, when like or similar materials are welded together, the areas of welding are not easily separated when opening the package. As such, the welded areas of the lid and/or tray, such as the illustrated flanges, tend to be destroyed as the two welded flanges are separated. This result would not leave flanges of the lid and tray with a smooth surface to be reclosed when the package is used for either saving unfished product or reusing the package for the storage of new product(s) or other item(s). Thus, the disclosed principles provide for a welding technique for use in welding the flanges of a rigid lid sealed onto a rigid tray, such that the two may be easily separated but still provide substantially smooth mating surfaces that permit the lid and tray to repeatedly reclosable such that the rigid package may be reused.

For this unique and advantageous ultrasonic welding technique, the disclosed principles provide for the inclusion of a unique delamination layer between the similar rigid materials used for forming the flanges of both the lid and the tray. Of course, instead of being located on flanges, the delamination structure disclosed herein may also be included in other advantageous areas of a rigid package. To ultrasonically weld two rigid plastics sufficiently to provide a hermetic seal, both rigid materials should have the same or very similar material composition or chemistry in the welding interphase area in order for a satisfactory seal to be provided between the two. The disclosed principles provide for the delamination layer to be provide on one or both of the two rigid materials, but behind the seal interphase area so that the hermitic seal may still be created. This delamination layer operates such that it peels apart (i.e., delaminates) as the ultrasonically sealed rigid material of the lid flange and rigid material of the tray flange are pulled apart while opening the package initially. Moreover, this delamination layer may be coextruded with the sealant layer on one or both of the rigid materials.

Looking at FIG. 4, illustrated is a block diagram presenting a cross-sectional view of a portion 400 of one of the rigid lid flange or rigid tray flange of a package constructed in accordance with the disclosed principles. Through this view, a coextruded sealant layer 420 can be seen formed immediately adjacent the inner surface 410 a of the rigid material 410 comprising either the ridge lid flange or the ridge tray flange. As mentioned above, other areas of a rigid package may also be constructed with the disclosed layer(s).

In exemplary embodiments, the rigid material 410 for the flange may itself be a laminated material, or it may be formed from a single layer of material. Exemplary materials for the rigid layer 410 may include compounds such as amorphous polyethylene terephthalate (APET), crystalline polyethylene terephthalate (CPET), polyethylene terephthalate glycol (PETG), polypropylene (PP), and polystyrene (PS), or even combinations of one or more of these materials. Each of these materials are safe for use in packages used for food products, and yet also provide the rigid structure for packages manufactured in accordance with the disclosed principles. However, other advantageous materials may also be employed, and no limitation to any particular material is intended or should be implied. In addition, the rigid material 410 to be ultrasonically welded may be formed to a thickness of about 15 to 30 mils, depending on the application. In exemplary embodiments, the coextruded sealant layer 420 would typically be formed as a much thinner layer, such as about only 2 mils thick. Other thicknesses may also be provided for the laminate sealant layer and the rigid layer, and the proportion in thickness between the two is determined by the composition of the rigid material 410, as well as the parameters employed for the ultrasonic welding of the two rigid materials.

Looking now at FIG. 5, illustrated is a block diagram presenting a cross-sectional close-up view of a portion 500 of an exemplary composition of the extruded sealant layer 420 shown in FIG. 4 in accordance with the disclosed principles. In this exemplary embodiment, the presently disclosed unique coextruded sealant layer 420 is comprised of four distinct layers. The sealant layer 420 may be formed at least in part by co-extrusion of multiple layers simultaneously, extrusion coating of another material, and the lamination of multiple layers together via extrusion lamination.

For the specific layers in this exemplary embodiment, immediately adjacent to the rigid material 410 is an adhesive layer 510, which in this embodiment is a polyethylene (PE) layer 510. The PE layer 510 operates as an adhesive joining the rigid material 410 and the delamination layer 520 located on its opposing surface. The delamination layer 520 serves as the peelable layer for the coextruded layers. As used herein a “peelable layer” is a layer of material that can be broken along a specified direction of travel, and which is typically easy to open in that the peelable layer requires less force to destroy than a destructive seal created by one or more joined layers. In one embodiment, the delamination layer 520 is comprised of an oriented polymer layer, such an ethylene propylene peel polymer (EP) layer. Such a polymer material may be formed with long polymeric molecules aligned in a given direction, causing the material to preferentially peel along that direction. Of course, one or more other materials having a similarly advantageous molecular structure, such as butylene, polybutylenes and ionomers, may also be used as the delamination layer 520.

Next in the coextruded stacked layer 420 is a barrier layer 530, which in exemplary embodiments may be comprised of a metalized polypropylene or ethylene-vinyl alcohol copolymer (EVOH), or one or more other barrier materials having similar properties. After the barrier layer 530, a sealant layer 540 is provided as the outermost layer of the stack. The sealant layer 540 may be comprised of ethylene vinyl acetate (EVA), but one or more other materials having similar properties may also be employed. For example, linear low-density polyethylene (LLDPE), ionomers and metallocenes, or blends thereof, may also be employed as the sealant layer 540. The sealant layer 540 provides one-half of the seal interphase (i.e., either for the rigid lid flange or the rigid tray flange) used between the two flanges so that a hermetic seal may be created by the ultrasonically welded flanges. In some embodiments, sandwiched between the barrier and sealant layers 530, 540 may be another adhesive layer, such as another PE layer or other adhesive. It should also be noted that additional layers may also be included for a coextruded stacked layer 420 adhered to a rigid packaging material as disclosed herein, so long as the delamination layer is included to provide the peelable characteristic that avoid destroying the ultrasonically welded rigid materials.

Looking now at FIG. 6, illustrated is a block diagram presenting a cross-sectional view of a portion 600 of both the rigid lid flange 610 a and the rigid tray flange 610 b of a reclosable package constructed in accordance with the disclosed principles. In this embodiment, only the rigid lid flange 610 a includes the disclosed delamination layer, although as mentioned above, both flanges 610 a, 610 b may include such a delamination layer. In such embodiments, either of the delamination layers may be peeled when the rigid flanges are pulled apart by a consumer opening the package.

As shown, exemplary materials are illustrated for the various layers of the coextruded sealant layers disclosed herein. But as noted previously, other exemplary materials having the same or similar properties and characteristics may alternatively or additionally be used. Specifically, APET is used as the rigid material 620, while EP is again used as the peelable delamination layer 630. In addition, EVOH is illustrated as being used for the barrier layer 640 of the coextruded stack, while EVA is provided as the sealant layer 650. For the rigid tray flange 610 b, the outermost layer is also and EVA sealant layer 660 so as to properly seal with the sealant payer 650 of the rigid lid flange 610 a through ultrasonic welding. In addition, the lid flange's barrier layer 670 is also formed of EVOH, and another adhesive layer 680 is used as an adhesive layer for adhering the coextruded stacked layer to the APET layer 690 used for the rigid tray flange 610 b.

In one exemplary embodiment, the above-noted materials were employed for their respective layers for rigid flanges to be ultrasonically welded using the techniques as disclosed herein. Also, in this embodiment the rigid lid flange 610 a was formed with a total thickness of 27 mils. More specifically, the rigid lid and its flange were formed of clear APET material to a thickness of 25 mils, and the coextruded stack having the delamination layer 630 was formed to a total thickness of 2 mils. The rigid tray flange 610 b was formed with a total thickness of 20 mils. Specifically, the rigid tray and its flange were formed of a black APET material to a thickness of 18 mils, and the coextruded stack of EVA 660, EVOH 670 and the adhesive layer 680 without a delamination layer was formed to a thickness of 2 mils.

These exemplary materials were ultrasonically welded to weld and seal the two rigid flanges 610 a, 610 b. The welded seal should provide a hermetic seal between the two rigid flanges, but be formed as a peelable seal instead of a destructive seal. It should be noted that one or more of the ultrasonic welding parameters can be varied to affect the resulting bond between the two flanges 610 a, 610 b. For example, in embodiments employing these exemplary materials at the stated exemplary thicknesses, the various ultrasonically welding parameters may be selected from the parameter set forth in Table 1.

TABLE 1 Weld Time 350 ms-450 ms Weld Energy 260 J-450 J Weld Power ~1500 W Weld Force ~210-250 lbf Trigger Force ~250 lbf Amplitude ~35 um

In other exemplary embodiments, the ultrasonic welding parameters may be substantially altered based on varying the thicknesses of the rigid plastic material being welded with a delamination layer in accordance with the disclosed principles. For example, a thickness of 18-28 mils for the rigid lid and its flange 610 a and again formed of clear APET material, while the coextruded stack having the delamination layer 630 is formed to a total thickness of 1.5-2.5 mils. The rigid tray flange 610 b in this embodiment may be formed with a thickness of also 18-28 mils, and again formed of a black APET material, while the coextruded stack of EVA 660, EVOH 670 and the adhesive PE layer 680 without a delamination layer may be formed to a thickness of 1.5-2.5 mils as well. In embodiments employing the disclosed layers of materials in these exemplary range of thicknesses, alternative ultrasonic welding parameters may be selected from the parameter set forth in Table 2.

TABLE 2 Weld Time 0.9 sec. Weld Energy ~250 J Weld Power ~540 W Weld Force ~150-225 lbf Trigger Force ~250 lbf Amplitude ~10.2 um

In yet other exemplary embodiments, alternative ultrasonic welding parameters may be selected from the parameter set forth in Table 3.

TABLE 3 Weld Time 900 ms-1100 ms Weld Energy ~305 J Weld Power ~1500 W Weld Force ~135 lbf Trigger Force ~250 lbf Amplitude ~10 um

The various ultrasonic welding parameters may be substantially altered based on the desired impact of the “dark line” or “wet line” area that represents the welded seal area between the flanges. More specifically, the seal area of the rigid package being sealed using the disclosed principles may be visible to consumers. In such package embodiments, a very consistent visible wet line around the perimeter of the package, or simply the welded/sealed areas, is typically desirable because of consumer visibility. Thus, a longer weld time combined with lower amplitude (e.g., the parameters of Table 2) may be employed (assuming the same or similar package materials and dimensions) to create a more visibly desirable wet line representing the seal area. However, in package embodiments where the seal area is not visible to consumers, or perhaps simply that the aesthetics of the seal area is not important, then, for example, a much faster weld time combined with a much higher amplitude (e.g., the parameters of Table 1) may be employed (again assuming the same or similar package materials and dimensions) to create seals more rapidly, regardless of the aesthetics of the wet line representing the seal area. In sum, one or more of the welding parameters may be altered as the materials are altered, the dimensions of materials are altered, and/or as the desired aesthetics of the weld area are altered, without departing from the broad scope of the disclosed principles.

Additionally, the ultrasonic welding anvil designs for use within the parameters listed in Table 1, Table 2 and Table 3 may also be selected from various advantageous designs. Exemplary designs for use with the disclosed principles include anvils with fine multilane, sharp multilane, 3 line, neural design-4-5 mm wide. Also, the dimensions and shapes of the welding anvils may be selected based on the size of the area to be ultrasonically welded, and even the reachability of the area to be welded. Moreover, the strength of the resultant seal may be adjusted by varying one or more of the amount of heat applied to the seal, the pressure applied to the seal, the length of time the heat and pressure are applied to the seal, as well as the geometry of the seal.

Looking now at FIG. 7, illustrated is a block diagram presenting a cross-sectional view of the portion 600 of both the rigid lid flange 610 a and the rigid tray flange 610 b shown in FIG. 6. More specifically, the illustrated portion 600 is shown after the ultrasonic welding of the two flanges 610 a, 610 b has been completed and a peelable hermetic seal has been created between the two in accordance with the disclosed principles. After this ultrasonic welding process, the EVA layers 650, 660 of the two flanges 610 a, 610 b, respectively, have been welding into a single EVA layer 655. By welding these two layers into a single EVA layer 655, the seal between the lid and tray flanges 610 a, 610 b is sufficient to provide a hermetic seal between the two parts of the rigid package.

Turning to FIG. 8, illustrated is a block diagram presenting a cross-sectional view of the portion 600 of lid flange 610 a and the tray flange 610 b shown in FIGS. 6 and 7. This figures illustrates the welded portion 600 after the rigid lid flange 610 a has been peeled away from the rigid tray flange 610 b. As a consumer lifts the rigid lid off of the rigid tray, the welded seal between the flanges 610 a, 610 b of these rigid components of the package is broken. Specifically, the seal is broken by the peeling of the lid flange 610 a off from the tray flange 610 b.

However, as discussed above, the ultrasonic welding of the same or very similar rigid plastics creates a destructive seal between these two layers. In this embodiment, the EVA layers 650, 660 are welded together and thus become a single layer 655. Thus, if one attempts to peel these layers apart, the result is a destruction of the now-formed single layer of material, which then prevents the two separated parts from maintain a consistent shape and mating surface so that the two parts could be easily reclosed together. Thus, in accordance with the disclosed principles, the peeling apart of the two flanges 610 a, 610 b does not actually occur where these two parts were ultrasonically welded together. Instead, the delamination layer 630 provides the precise location where the rigid lid flange 610 a may be peeled away from the rigid tray flange 610 b. Accordingly, the force required to peel apart the delamination layer 630 must be significantly less than the force required to destructively peel the now-single EVA or other welded sealant layer 655 back into two separate parts.

If the two rigid flanges 610 a, 610 b are made from two materials with sufficient difference from one another, but still capable of being ultrasonically welded to each other, to provide an easy peelable seal, the seal between the two rigid flanges would not be sufficient to provide a hermetic seal between the lid and tray. This is because of the need for welded materials to be the same or very similar in order to provide a hermetic seal when ultrasonically welded. Thus, the disclosed principles are particularly advantageous for use in rigid packages intended for use to hold food products due to the creation of a hermetic seal between the rigid lid and rigid tray. But the disclosed principles also provide the additional advantages of providing a peelable seal, rather than a destructive seal, between the rigid lid and rigid tray so that the rigid package is actually reclosable for later use. As illustrated in FIG. 8, once the delamination layer 630 is peeled apart when the flanges 610 a, 610 b are initially separated, a first portion 630 a of the delamination layer is left on what remains as the lid flange 610 c, and a second portion 630 b of the delamination layer is now found on the opened tray flange 610 d. It should be noted that in exemplary embodiments, the extruded stack on the lid flange is typically no more than a couple of mils in thickness, and thus the remaining flanges 610 c, 610 d, do not typically look any different to a consumer than they would have before the ultrasonic welding took place.

Moreover, the oriented polymer composition of the delamination layer 630 results in a smooth, uniform delamination or peeling/splitting of this layer 630 into the two remaining components 630 a, 630 b. This uniform delamination allows the new mating surfaces of the lid and tray flanges 610 c, 610 d to have a smooth finish similar to the original mating surfaces of the flanges 610 a, 610 b illustrated in FIG. 6. It should also be noted that although FIG. 8 illustrates, for exemplary purposes, the delamination layer 630 rupturing in the middle, the layer 630 may also be configured to rupture (i.e., delaminate) more on one side than the other, and thus it should not be assumed that the delamination layer 630 necessarily delaminates exactly in the middle. Moreover, the delamination layer 630 may be configured to substantially delaminate from the its adjacent layer, if desired. In any case, by providing an intended place of delamination, the remaining substantially smooth mating surfaces could not have been formed by the peeling apart of a destructive seal, such as the single welded EVA layer 655. By providing these remaining mating surfaces as substantially smooth, the rigid lid can repeatedly be reclosed and then removed from the rigid tray without any destroyed or uneven jagged remaining flanges surfaces obstructing the reclosing of the rigid package. Without any such obstruction, the lid and tray skirts of a rigid package as disclosed herein may be joined, for example, in the manner discussed above.

Looking at FIG. 8A and FIG. 8B, illustrated are plots 800 a, 800 b of peel force used to peel apart 16 Specimens of two ultrasonically welded rigid plastics have the characteristics of the materials discussed with reference to the ultrasonically welding parameters in Table 1. As illustrated, the average range of peel force for these 16 specimens is about 1.82 lbf to 2.28 lbf, or more specifically an average peel force of about 2.0 lbf. The specific measurements for each of the 16 specimens are set forth in Table 4.

TABLE 4 Extension Maximum at Maximum Specimen Load [lbf] Load [in] no 1 >1.96908 >0.87549 272 26 2 >1.99148 >0.99552 261 15 3 >2.05786 >0.85552 263 17 4 >1.88360 >1.01548 287-41 5 >2.00356 >0.87549 284-38 6 >1.95567 >0.89550 282-36 7 >2.17763 >0.99548 252-06 8 >1.94375 >0.91550 260-14 9 >1.99329 >0.87549 262-16 10 >2.16454 >0.99552 277-31 11 >2.08382 >0.97549 293-47 12 >2.04063 >0.97549 267-21 13 >2.28097 >1.03550 273-27 14 >2.17561 >1.05550 278-32 15 >2.04073 >0.95552 292-46 16 >1.82179 >0.75550 280-34 Average >2.03650 >0.94050 Standard deviation 0.11897 0.08017 Maximum 2.28097 1.05550 Minimum 1.82179 0.75550

For other pairs of rigid plastics having other thicknesses, which in turn employ different ultrasonic welding parameters such as those set forth in Table 2, the peel force may be slightly increased or decreased depending on the varied thicknesses. As such, the overall average range of peel force for peeling two rigid plastics having a delamination layer as disclosed herein is typically about 1.5 lbf to 4.0 lbf.

Referring now to FIG. 9, illustrated is a top view of a second embodiment of a rigid multi-compartment reclosable package 900 constructed in accordance with the disclosed principles. This embodiment of the package 900 is again formed having four sides, and generally in the shape of a square when viewed from the top, with the four corners of the package 900 again rounded off. The package 900 again comprises a rigid lid 905 fitted completely over a rigid tray 910. The rigid lid 905 of the package 900 is again semi-transparent in this embodiment, which as before allows visibility of a piece of product 915 being held within the package 900.

This embodiment of the package 900 again includes a lid tab 905 a and tray tab 910 a, which may be grasped by a consumer and pulled in opposite directions so that the lid tab 905 a is pulled upwardly and the tray tab 910 a is pulled downwardly to separate the lid 905 from the tray 910. However, this embodiment of the tabs 905 a, 910 a are formed in a rectilinear shape, whereas a triangular shape was used in the prior package embodiments discussed above. Texture features 905 b and 910 b may again be provided on the respective tabs 905 a, 910 a as before, to assist the consumer in maintaining their grasp of the tabs 905 a, 910 a. In this embodiment, the rectangular shape of the tabs 905 a, 910 a permits an elongated shape for the texture features 905 b, 910 b, whereas in prior package embodiments, the features were formed in an angular shape corresponding to the triangular shape of the prior texture features.

In some embodiments of a package as disclosed herein, grasping tabs are not provided on the flanges. Instead, inset portions along the lid flanges may be formed so as not to laterally extend as far out as the tray flanges, while the other portions of the lid flanges are formed coextensive with the tray flanges. As such, portions of the tray flange are exposed when viewing from above the package with the lid secured onto the tray. Using this non-coextensive portion of the lid flange that reveals portions of the tray flange, a consumer is able to easily separate the tray flange from the inset portion of the lid flange by simply pressing down on the exposed portion of the tray flange. By slightly pressing down this exposed area of the tray flange, the consumer can then easily separate the lid flange from the tray flange peeling the flanges apart as described herein when the rigid flanges have been hermetically sealed, or with enough force to overcome the securing feature(s) if the package has simply been reclosed after initial opening. In either case, the consumer may then pull the lid off of the tray.

Turning to FIG. 10, illustrated is a side cross-sectional view of the package 900 of FIG. 9 taken along line 10-10. From this cross-sectional view, both the lid 905 and the tray 910 of this embodiment of the package 900 can be seen. As before, this view again shows the uniquely shaped raised walls 920 that extend from the bottom surface of the rigid tray 910 to the underside of the lid 905 to create the multiple compartments on the tray 910. As before, while four product compartments are again provided by the walls 920 in this embodiment, any number of compartments for the package 900 may also be provided within the scope of the disclosed principles.

In this embodiment, the dividing walls 920 again are tapered or sloped from the center of the tray 910 towards the outer periphery of the tray 910. The slope of the walls 920 are again such that the bottom periphery of the tray 910 includes a raised lip 910 c that helps secure the product 915 held on the tray 910 from sliding off of the tray 910 when the lid 905 is removed. This tapered structure for the walls 920 again permits partial viewing of the product 915 within the package 900 from the side by a consumer in those embodiments having a transparent or semi-transparent lid 905. As also mentioned above, the sloped walls 920 allow easier grasping of the product 915 on the tray 910 by a consumer's fingertips once the lid 905 is removed from the tray 910.

Formation of the walls 920 and the tray 910 can again be done in a single, unitary piece of rigid material by any viable plastic formation technology, or the walls 920 may simply be attached to the interior, bottom surface of the tray 910. In such latter embodiments, the walls 920 may all be formed in a single piece, and then that piece attached or otherwise affixed to the interior, bottom surface of the tray 910, or one or more of the walls 920 may be formed separately, and then the two or more pieces comprising the walls 920 attached or otherwise affixed to the interior, bottom surface of the tray 910. As mentioned above, the walls 920 maybe be formed to provide any number of compartments on the tray 910 for holding product(s) 915, as well as that the compartments created on the tray 910 can be or substantially equal dimensions and sizes, or may be formed in any size and shape with respect to one another. Similarly, the dimensions and slope of the walls 920 can also as before be different from those in this illustrated embodiment, in the same manner as discussed above for the prior embodiments of package constructed in accordance with the disclosed principles.

Also once again included again in this embodiment of the package 900 are a lid skirt 925 and a tray skirt 930 to be used as a closing feature for the package 900, in the manner discussed above for the prior embodiment. However, in this embodiment of the package 900, the skirts 925, 930 are now shown as being formed in an outward and upward configuration and coextensive with one another in corresponding complimentary shapes. Despite having skirts 925, 930 that are formed upwardly, this embodiment of the package 900 again includes flanges 925 a, 930 a laterally extending outward from the ends of each skirt 925, 930, similar to the package 200 of FIGS. 1-3. The flanges 925 a, 930 a in this embodiment are again formed coextensive with one another, and may be used create a hermetic seal for the package 900 that may also be peeled apart by the consumer, in accordance with the disclosed principles. The formation of such a seal using the flanges 925 a, 930 a, as mentioned above, allows the package 900 to be used for any of the types of food products requiring hermetic sealing. Also as before, the flanges 925 a, 930 a in this embodiment are flat and extend horizontally from their corresponding skirts 925, 930; however, they may also be formed extending in other directions as well, and may be formed having a shape other than flat.

FIG. 11 illustrates a close up cross-sectional detail view of a portion of FIG. 10. This close up view illustrates the joined lid and tray skirts 925, 930 joined together when the lid 905 is closed onto the tray 910. From this close up view, the complimentary, outward and now upwardly formed shapes of the lid skirt 925 and the tray skirt 930 can be seen clearly. As before, the lid skirt 225 may be secured over the tray skirt 930 when fitting the lid 905 onto the tray 910. Also as before, the rigid materials used to form the lid 905 and the tray 910 provide a minimum amount of resiliency along with flexibility to the corresponding skirts 925, 930. This results in the skirts 925, 930 maintaining their overlapping positioning so as to keep the lid 905 snapped onto the tray 910. However, in this embodiment the small amount of flexibility in the materials allows the lid skirt 925 to be flexed inwardly, away from the tray skirt 930 temporarily so that the lid 905 may be lifted off of the tray 910.

Also, a securing feature 935 may also be seen on the package 900; however, in this embodiment, the securing feature 935 is formed as corresponding convex (outward) curvatures on the upward, vertical portions of the skirts 925, 930. While this securing features 935 again assists in securing the lid 905 onto the tray 910, this embodiment of the securing feature 935 is provided as a single set of corresponding curved features that are formed around the entire skirts 925, 930 of the lid 905 and tray 910. Opening the securing feature 935, however, is similar to other embodiments in that the lid tab 905 a and the tray tab 910 a may be pulled apart by the consumer to overcome the securing feature 935 and thus separate the lid skirt 925 from the tray skirt 930 to open the package 900. Of course, other shapes for such a securing feature 935 that circumscribes the skirts 925, 930 of the package 900 may also be employed. To provide the snap-fitting of the lid 905 onto the tray 910, the securing feature 935 in this embodiment is formed all the way around the lid and tray skirts 925, 930 of the package 900. Although this embodiment of the package 900 includes only a single securing feature 935 formed around the perimeter of the skirts 925, 930, other rigid package embodiments may include two or more such features 935 or may include multiple securing features staggered around various points of the perimeter of the package, such as those discussed in the above package embodiments. Also, the securing features 935 may be comprise of a combination of the illustrated securing feature 935 along with one or more other features, such as the capsule shaped securing features of the prior discussed package embodiments.

In some embodiments of a rigid package as disclosed herein, grasping tabs are not provided on the flanges. Instead, inset portions along the lid flanges may be formed so as not to laterally extend as far out as the tray flanges, while the other portions of the lid flanges are formed coextensive with the tray flanges. As such, portions of the tray flange are exposed when viewing from above the package with the lid secured onto the tray. Using this non-coextensive portion of the lid flange that reveals portions of the tray flange, a consumer is able to easily separate the tray flange from the inset portion of the lid flange by simply pressing down on the exposed portion of the tray flange. By slightly pressing down this exposed area of the tray flange, the consumer can then easily separate the lid flange from the tray flange peeling the flanges apart as described herein when the rigid flanges have been hermetically sealed, or with enough force to overcome the securing feature(s) if the package has simply been reclosed after initial opening. In either case, the consumer may then pull the lid off of the tray.

In the numerous embodiments of the inventive subject matter disclosed herein, such embodiments may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

The Abstract is provided to comply with 37 C.F.R. § 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

The description has made reference to several exemplary embodiments. It is understood, however, that the words that have been used are for description and illustration, rather than words of limitation. Changes may be made within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the disclosure in all its aspects. Although this description makes reference to particular means, materials and embodiments, the disclosure is not intended to be limited to the particulars disclosed; rather, the disclosure extends to all functionally equivalent technologies, structures, methods and uses such as are within the scope of the appended claims. 

What is claimed is:
 1. A hermetically sealed package, comprising: a first flange comprised of a rigid plastic and having a first mating surface; a first laminated layer disposed on the first mating surface of the first flange, wherein the first laminated layer comprises a delamination layer and a sealant layer positioned as the outermost layer of the first laminated layer; a second flange comprised of a rigid plastic and having a second mating surface configured to be ultrasonically welded to the first mating surface; a second laminated layer disposed on the second mating surface of the second flange, wherein the second laminated layer comprises a sealant layer positioned as the outermost layer of the second laminated layer; and wherein the first and second mating surfaces with the first and second laminated stacks interposed are ultrasonically welded to one another such that the first and second sealant layers are hermetically sealed.
 2. A package according to claim 1, wherein the delamination layer comprises ethylene propylene polymer (EP).
 3. A package according to claim 1, further comprising a barrier layer disposed between the delamination layer and the sealant layer.
 4. A package according to claim 3, wherein the barrier layer comprises ethylene-vinyl alcohol copolymer (EVOH).
 5. A package according to claim 1, further comprising an adhesive layer disposed between the delamination layer and the rigid plastic of the first flange.
 6. A package according to claim 5, wherein the adhesive layer comprises polyethylene (PE).
 7. A package according to claim 1, wherein one or both of the first and second sealant layers is comprised of ethylene vinyl acetate (EVA).
 8. A package according to claim 1, wherein the sealant layer of the first laminated layer and the sealant layer of the second laminated layer are comprised of the same material.
 9. A package according to claim 1, wherein one or both of the rigid plastic comprising the first and second flanges comprises amorphous polyethylene terephthalate (APET), crystalline polyethylene terephthalate (CPET), polyethylene terephthalate glycol (PETG), polypropylene (PP), and polystyrene (PS), or a combination of one or more of these materials.
 10. A package according to claim 1, wherein the first and second flanges comprise APET; wherein the first laminated layer comprises: a delamination layer comprising EP, an adhesive layer comprising PE between the first mating surface and the delamination layer, a barrier layer comprising EVOH on the delamination layer, a sealant layer comprising EVA disposed on the barrier layer; and wherein the second laminated layer comprises: a barrier layer comprising EVOH, an adhesive layer comprising PE between the second mating surface and the barrier layer, a sealant layer comprising EVA disposed on the barrier layer.
 11. A package according to claim 10, wherein the first flange is formed to a thickness of 18-28 mils and the first laminated layer is formed to a thickness of 1.5-2.5 mils, and wherein the second flange is formed to a thickness of 18-28 mils and the second laminated later is formed to a thickness of 1.5-2.5 mils.
 12. A package according to claim 1, wherein the delamination layer is configured to be peeled apart with a force in the range of 1.5 lbf to 4.0 lbf.
 13. A package according to claim 1, wherein the second laminated layer comprises a delamination layer disposed between the sealant layer and the second mating surface.
 14. A package according to claim 1, wherein the first laminated layer on the first mating surface is coextruding with the first flange.
 15. A method for providing a peelable hermetic seal on a rigid package, the method comprising: providing a first flange comprised of a rigid plastic and having a first mating surface; forming a first laminated layer on the first mating surface of the first flange, wherein the first laminated layer comprises a delamination layer and a sealant layer positioned as the outermost layer of the first laminated layer; providing a second flange comprised of a rigid plastic and having a second mating surface configured to be ultrasonically welded to the first mating surface; forming a second laminated layer on the second mating surface of the second flange, wherein the second laminated layer comprises a sealant layer positioned as the outermost layer of the second laminated layer; and ultrasonically welding the first and second mating surfaces with the first and second laminated stacks interposed therebetween such that the first and second sealant layers are hermetically sealed to one another.
 16. A method according to claim 15, wherein the delamination layer comprises ethylene propylene polymer (EP).
 17. A method according to claim 15, further comprising disposing a barrier layer between the delamination layer and the sealant layer.
 18. A method according to claim 17, wherein the barrier layer comprises ethylene-vinyl alcohol copolymer (EVOH).
 19. A method according to claim 15, further comprising disposing an adhesive layer between the delamination layer and the rigid plastic of the first flange.
 20. A method according to claim 19, wherein the adhesive layer comprises polyethylene (PE).
 21. A method according to claim 15, wherein one or both of the first and second sealant layers is comprised of ethylene vinyl acetate (EVA).
 22. A method according to claim 15, wherein the sealant layer of the first laminated layer and the sealant layer of the second laminated layer are comprised of the same material.
 23. A method according to claim 15, wherein one or both of the rigid plastic comprising the first and second flanges comprises amorphous polyethylene terephthalate (APET), crystalline polyethylene terephthalate (CPET), polyethylene terephthalate glycol (PETG), polypropylene (PP), and polystyrene (PS), or a combination of one or more of these materials.
 24. A method according to claim 15, wherein the first and second flanges comprise APET; wherein the first laminated layer comprises: a delamination layer comprising EP, an adhesive layer comprising PE between the first mating surface and the delamination layer, a barrier layer comprising EVOH on the delamination layer, a sealant layer comprising EVA disposed on the barrier layer; and wherein the second laminated layer comprises: a barrier layer comprising EVOH, an adhesive layer comprising PE between the second mating surface and the barrier layer, a sealant layer comprising EVA disposed on the barrier layer.
 25. A method according to claim 24, wherein the first flange is formed to a thickness of 18-28 mils and the first laminated layer is formed to a thickness of 1.5-2.5 mils, and wherein the second flange is formed to a thickness of 18-28 mils and the second laminated later is formed to a thickness of 1.5-2.5 mils.
 26. A method according to claim 25, wherein ultrasonically welding the first and second mating surfaces with the first and second laminated stacks interposed therebetween further comprising employing welding parameters of: 350 ms-450 ms weld time; 260 J-450 J weld energy; ˜1500 Watts weld power; ˜210-250 lbs weld force; ˜250 lbs trigger force; and ˜35 um amplitude.
 27. A method according to claim 25, wherein ultrasonically welding the first and second mating surfaces with the first and second laminated stacks interposed therebetween further comprising employing welding parameters of: 900 ms-1100 ms weld time; 305 J weld energy; ˜1500 Watts weld power; ˜135 lbs weld force; ˜250 lbs trigger force; and ˜10 um amplitude.
 28. A method according to claim 15, wherein the delamination layer is configured to be peeled apart with a force in the range of 1.5 lbf to 4.0 lbf.
 29. A method according to claim 15, wherein the second laminated layer comprises a delamination layer disposed between the sealant layer and the second mating surface.
 30. A method according to claim 29, wherein forming a first laminated layer on the first mating surface of the first flange further comprises coextruding the first laminated layer with the first flange. 